During the process of concentration and minimization of high salinity wastwater

residual Ca(Ⅱ)easily forms calcium carbonate and calcium sulfate precipitates

which affects the long-term stable operation of the membrane concentration system. In this study

the adsorption mechanism of residual Ca(Ⅱ) from high salinity wastwater by Amberlite IRC 747 ion exchange resin

Letwatit TP 260 ion exchange resin and D113 ion exchange resin is studied by static adsorption system. The results show that

the adsorption capacities of three ion exchange resins increases as the contact time is prolonged and the reaction temperature is increased

while increasing the salt content prohibits the adsorption of Ca(Ⅱ). Besides

Langmuir isotherms are fitted better than Freundlich isotherms

and the theoretical maximum adsorption capacities of IRC 747

TP 260 and D113 are 81.43 mg/g

75.08 mg/g and 109.17 mg/g

respectively. The adsorption of Ca(Ⅱ) by ion exchange resins is in accordance with the pseudo-second-order kinetics

the order of initial reaction rate is IRC 747 D113 TP 260. In addition

the thermodynamic parameters such as Gibbs free energy change(?G_o)

enthalpy change(?H_o)

entropy change(?S_o)and activation energy(E_a) of the ion exchange reaction reveals that the adsorption of Ca(Ⅱ) by these three ion exchange resins is effective

endothermic and spontaneous.